Old fashioned down shifting and braking

[kickstartcarl]

I had my roundabout approach corrected recently by a HGV instructor and though you lot may be able to help me understand

Driving a car in to a roundabout 70mph in 5th gear....

My normal routine is to brake, change to 4th, then to third, or what ever gear is the best for the speed of the corner matching revs to road speed as i go...

The instructor told me that moving through 4th gear on the way down was a waste. In modern cars brakes are for slowing down and gears are for going forward. Old lorries and cars used to have to use engine braking to assist the gears. Fair point I thought and tried it out.

Why do we change down through gears concentrate on heel toeing when in a modern car you can brake really late, select the right gear and accelerate through...

PS, I hope this a good discussion more that anything an I still plan on blasting my way down through the gears with twisted ankles as much as I can even it is just for fun.

Thanks
Carl

[vonhosen]

Think about what your objectives are & what way best achieves those objectives........go with that.

[WhoseGeneration]

kickstartcarl said:

I had my roundabout approach corrected recently by a HGV instructor and though you lot may be able to help me understand

Driving a car in to a roundabout 70mph in 5th gear....

My normal routine is to brake, change to 4th, then to third, or what ever gear is the best for the speed of the corner matching revs to road speed as i go...

The instructor told me that moving through 4th gear on the way down was a waste. In modern cars brakes are for slowing down and gears are for going forward. Old lorries and cars used to have to use engine braking to assist the gears. Fair point I thought and tried it out.

Why do we change down through gears concentrate on heel toeing when in a modern car you can brake really late, select the right gear and accelerate through...

PS, I hope this a good discussion more that anything an I still plan on blasting my way down through the gears with twisted ankles as much as I can even it is just for fun.

Thanks
Carl

What is your age?

[7mike]

IMHO most drivers of manual vehicles can not judge accurately when to begin braking to loose sufficient road speed on approach to junctions/ roundabouts etc. eg. at the end of a fast stretch of DC I use regularly I know that the brakelights of cars ahead will come on far too early, resulting in unnecessary downchanges simply to maintain momentum just to get to the giveway point. In reality, most of the down changes are so close together that the clutch is down most of the time anyway (if it comes up at all) so any percieved advantage of engine braking is lost. In my experience it then results is missed (safe) opportunities to proceed. Problems arise when this method of 'brakes to slow, gears to go' is used too rigidly, flexibility is needed.

[kickstartcarl]

What is your age?
[/quote]

26 - why do you ask?

[GreenV8S]

kickstartcarl said:

My normal routine is to brake, change to 4th, then to third, or what ever gear is the best for the speed of the corner matching revs to road speed as i go...

Are you saying that after the braking is over you change down through the gears until you reach the right gear for your speed - and your advisor suggested you do a block change instead? If so I'd agree with your advisor.

On the other hand if you're changing down to 4th and then staying in fourth for a while, and there's some benefit to being in 4th rather than 5th at that time, there may be a justification for what you're doing. But so far it's not apparent to me.

[davepoth]

Reasons for heel-and-toe:

1)syanchronise the transmission to avoid gearbox wear
2)keep the car balanced under heavy braking (avoid shift lock)
3)keep the engine at the correct speed for the fastest possible corner exit

and of those the first two are definitely not needed in modern driving, and you need to be exceptionally sure that the roundabout is clear before you need 3). Your HGV driving friend was right, but it's still more fun "our" way.

[Dr Jekyll]

kickstartcarl said:

What is your age?

26 - why do you ask?

I suspect he was asking because your 'down through every gear' technique is usually only used by those who learnt to drive in the days before Borg met Warner, or even Rolls met Royce.

[Tyranosawus]

I tend to stay on the gas whilst keeping an eye on what's going on around. Brake late and hard let the abs which is fitted to the majority of modern cars do it's work. H&t to keep the revs matched then get a nice rapid safe crossing of said roundabout. If I'm in an older or crapper car I might use the box to help the braking process and be mindful of the probable absence of abs etc. I change my driving style at junction roundabouts to fit in with the car I'm in and conditions at the time. My default is my first scenario given suitable conditions.

[GreenV8S]

Tyranosawus said:

Brake late and hard let the abs which is fitted to the majority of modern cars do it's work.

You plan to brake hard enough for the ABS to be required? That's a rather extraordinary strategy in normal driving.

[handpaper]

I was taught the same "engine for go, brakes for slow" technique when I did HGV 1 last month. It's done to stop you relying so much on engine braking, which doesn't have much effect on a 40-ton artic.

[WhoseGeneration]

Dr Jekyll said:

kickstartcarl said:

What is your age?

26 - why do you ask?

I suspect he was asking because your 'down through every gear' technique is usually only used by those who learnt to drive in the days before Borg met Warner, or even Rolls met Royce.

Indeed.
Then, whatever safe method suits any individual is ok by me.
But I'm old and remember a drive out in 1968, in my Triumph Spitfire, with a Traffpol, who asked me to demonstrate abrupt slowing without using the brakes.

Eta, apologies, quoting seems to be awol.

Edited by WhoseGeneration on Sunday 11th October 02:54

[7mike]

GreenV8S said:

Tyranosawus said:

Brake late and hard let the abs which is fitted to the majority of modern cars do it's work.

You plan to brake hard enough for the ABS to be required? That's a rather extraordinary strategy in normal driving.

Must be fun on snow!!
It's amazing how after all this time with ABS fitted to cars there is so little understanding about what it does/does not do. I can't wait to hear the urban myth that will pop up as ESP becomes more commonplace(although thinking about it, I seem to remember reading some of that already on an older thread).

Tyranosawus, ABS is a safety feature which generally kicks in when things have gone wrong. Although happy to have both Active & Passive Safety Systems fitted, I'd no sooner use ABS than I would the airbags!

Edited by 7mike on Sunday 11th October 07:53

[RobM77]

In answer to the OP's questions: Block or sequential changing is your own decision. Block changing is obviously less hassle, but it can be tricky in a high geared car as you'll be revving impossibly low in top gear at 30mph before the roundabout. You also have to know what gear you're going to eventually need, which is not always obvious. Oh, and certain changes may not suit your gearbox. As for 'accelerating through' you need to pick up your old Physics textbooks! ;-) you'll be putting the car in an understeer stance which will wear your front tyres out and severely reduce your chances of avoiding an accident because you're not distributing the grip evenly round the car.

I'd say ignore the person who told you this and continue as you were, but experiment with block changing and see how it suits your car.

[Mr Grayson]

Controversial stuff

If you brake in a straight line, and feather the clutch when the engine starts to labour, you can drop from 70+ to nearly 0 in top gear (be that 4th, 5th or 6th) in any car, without causing any undue problem. Because the car is slowing and the wheels are beginning to drive the engine in the latter stages, rather than the other way round, the "impossibly low revs" don't really cause a problem.

Approach roundabouts "planning to stop" with "looking to go" as a secondary thought. That way your speed will be correct as you approach the give-way line. If it's all clear, you can select whichever gear seems appropriate (normally 2nd or 3rd) and carry on. If not, no harm is done. You continue braking, and glide to a stop at the line (just as you planned to anyway).

[Conian]

you brake for roundabouts and junctions? poofs!

sorry

[RobM77]

Mr Grayson said:

If you brake in a straight line, and feather the clutch when the engine starts to labour, you can drop from 70+ to nearly 0 in top gear (be that 4th, 5th or 6th) in any car, without causing any undue problem.

Or you could drive with mechanical sympathy instead

I believe in flowing with a car and being sympathetic, not fighting it and forcing it into doing things it doesn't want to do. I find it far more relaxing to drive like that, but I guess we're all different!

Edited by RobM77 on Monday 12th October 00:20

[Tyranosawus]

GreenV8S said:

Tyranosawus said:

Brake late and hard let the abs which is fitted to the majority of modern cars do it's work.

You plan to brake hard enough for the ABS to be required? That's a rather extraordinary strategy in normal driving.

I figure if it's there I might as well use it. I find braking that hard and late actualy buys thinking time when you get used to it.

[fadeaway]

Tyranosawus said:

GreenV8S said:

Tyranosawus said:

Brake late and hard let the abs which is fitted to the majority of modern cars do it's work.

You plan to brake hard enough for the ABS to be required? That's a rather extraordinary strategy in normal driving.

I figure if it's there I might as well use it. I find braking that hard and late actualy buys thinking time when you get used to it.

I must have misunderstood your explanation, because that sounds simply dangerous! Given the benefits of ABS, are you suggesting that you brake so hard that:

1). Without ABS you would induce a skid, or
2). that you break so late that you are unable to lose sufficient speed to make it around the roundabout and therefore have to continue braking through the turn?

[Tyranosawus]

fadeaway said:

I must have misunderstood your explanation, because that sounds simply dangerous! Given the benefits of ABS, are you suggesting that you brake so hard that:

1). Without ABS you would induce a skid, or
2). that you break so late that you are unable to lose sufficient speed to make it around the roundabout and therefore have to continue braking through the turn?

Without ABS cadence braking is the order of the day. I'm not advocating doing it when there's much other traffic around or the conditions are unsuitable. With a bit of practice you learn how hard you have to brake to slow sufficiently to not be braking into the turn. You'd be amazed how much of a compensating effect hard late braking has on maintaining a consistant average speed and keeping traffic flowing better as long as you maintain awareness of what people directly around you are doing and you adapt accordingly. For instance don't go there if you have someone right up your chuff or you can see there's a busy roundabout or road ahead. I do most of my driving when the roads are quiet / empty, I always adapt my driving to suit conditions / traffic at the time. I have been known to use the rev limiter as a brake on suitable occasions as well. On a quiet / empty straight section of NSL when someone has helpfuly installed one of those stupid little raised resin mini roundabouts for no apparent reason ( but that's a whole different rant). I also use my left foot to brake as much as my right foot, especialy whilst on a spirited drive on quiet NSL roads.

Edited by Tyranosawus on Monday 12th October 11:21